SlackMessagePostedListener Not Working

[roxanne-thiri]

Hello, can anyone help me for using SlackMessagePostedListener?
Previous RTM API version was working well to handle SlackMessagePostedListener.
However, the new Granular Scope with WebSocket Mode won't be listening any event that is created. This below part is not able to reach no matter how I put the scopes for the bot and tried to subscribe the Event API as well.

If you have any idea, please kindly help me.

		SlackMessagePostedListener messagePostedListener = new SlackMessagePostedListener()
	    {
			@Override
			public void onEvent(SlackMessagePosted event, SlackSession session) {
				// This part is not able to reach no matter how I put the scopes for the bot and tried to subscribe the Event API as well
				System.out.println(event.getChannel().getName());
			}
	    };
		session.addMessagePostedListener(messagePostedListener);